Towards a new field of physics: Coherent Caloritronics

Quantum electronics is now a mature field of physics in the sense that its basis is well understood, and in that it is a natural playground to develop quantum technology. Despite this tremendous success in both the understanding and harnessing of charge transport, very little is known regarding the quantum properties of heat transport. The COHERENT CALORITRONICS group at CnrNano activity aims at strengthening the understanding of phase-coherent heat transport in mesoscopic superconducting circuits and at developing new strategies for exploiting it, while developing new coherent caloritronic devices. In analogy to electronics, caloritronics encompasses the techniques for controlling, distributing, storing and converting heat ("calor" in Latin). After showing the existence of a phase-coherent component (i.e., tunable for instance with a magnetic flux) of thermal currents flowing between two temperature-biased superconductors [1], researchers developed a device that allow heat to flow preferentially in one direction, providing the homologue of an electrical diode [2]. Now the team realized the building block to demonstrate the exact correspondence in the phase engineering of charge and heat transport [3].
The latter device consists in a double loop Josephson modulator able to provide large magnetic-flux-driven temperature oscillations and a full control over the coherent heat current component. The modulator is robust against unavoidable structure asymmetries and offers the possibility to obtain exotic thermal interference patterns with an enhanced sensitivity to magnetic flux variations. Furthermore, it opens the way to the realization of advanced caloritronic devices, such as thermal splitters, heat pumps and time-dependent electronic engines. The latter are expected to become key tools in a huge number of low-temperature circuits, in order to achieve an accurate energy control for quantum computing, solid state cooling, radiation detection and thermal logic.